Dunlop was a hugely popular figure in the motorcyling world
Former TT and North West 200 star Phillip McCallen has described the late Robert Dunlop as a "motorcycling icon".
Dunlop died on Thursday after suffering severe chest injuries in a crash during a practice session at the North West 200 road races in Northern Ireland.
McCallen, who retired in 1999, said Dunlop was a tough competitor who could not stay away from the sport.
"Racing and motorcycles are in the Dunlop blood and Robert could not give it up," said the 11-times TT winner.
"He did try to retire but he got a real buzz from riding motorcycles. It is difficult to describe the feeling - you need to have done it yourself."
Liam Beckett, who had been Dunlop's mechanic for more than 20 years, said: "I am just numb. People will be waking up to the news that Ballymoney has lost another of its favourites sons.
"It is a dagger in the heart for us all."
Mervyn Whyte, clerk of the course for the North West 200, told BBC Radio 5 Live: "It's a major loss to the sport.
"Robert was a major help to me at the NW200 over the years.
"With just a phone call he would be with me in a fairly short space of time to help me with any safety issues, to give me advice and to look at what my plans were for the event itself.
"He was always a great inspiration.
"He had a great sense of humour and he was always very proud to be associated with the event over the years.
"He was a great ambassador for the sport in this country and further circles as well. It's a major tragedy for sport in this country."